1. Field of the Invention
The present invention relates generally to the field of rivet guns, and more particularly to a device to control the depth of travel of a rivet die of a rivet gun to limit damage to the installation surface area.
2. Background Information
Rivet guns are used for driving rivets, staples, nails, and other fasteners (hereinafter fasteners) into a surface of an object. A problem with present rivet guns is the inability to control the fastener driving depth. This is due to the inconsistency in driving depth depending on how much driving and recoiling force is created.
It is desirable to allow one to control the depth to which the fastener will be driven. Different applications require different driving depths for the fasteners. For some applications it is desirable to drive the fasteners so they are countersunk below the surface of the substrate. For other applications it may be desirable to have the fastener head flush with the surface of the substrate. In other circumstances, it may be required for the fastener head to stand off from the surface of the substrate.
Many fastener driving tools have attempted to control fastener driving depth. Effectively controlling driving depth has been difficult in the past because each fastener is usually driven with the same amount of energy each time that the tool is fired. This has been known to cause fasteners to be driven to an inconsistent depth when there were variations in the density of the surface of the object. This is especially problematic in the aerospace industry where a rivet gun may be the only means to install a fastener. The use of a rivet gun presents several obstacles. First, the rivet gun may damage the structure of an aircraft should the rivet die of the rivet gun extend too far and contact the surface of the aircraft. If the rivet die contacts the surface of the aircraft with too much force, the rivet die will generally damage the structure of the aircraft. Second, the use of a rivet gun may cause damage to the countersunk areas of the aircraft. If the fastener is fully seated, there is a possibility of micro-cracking the countersunk area of the hole by the rivet gun.
Therefore, it would be desirable to provide a device that overcomes the above problems. The device will allow controlled depth riveting of fasteners in order to prevent damage to a structure being fastened.